I don’t think it’s revenge as much as it is that Florre just wants everything that Dahlia has. I think that Floree was just born evil bc she likes to make other people’s lives living hell. I think she only started thinking of getting revenge after she read that letter that explained that she is an MC and that Dahlia was super mean to her in the novel.
Atfirst she's confused why dahlia doesn't buy her kindness like the others (since she's been using it for her favor so far) and i guess dahlias actions kinda piss her of since she's greater than her (in every which way) stupid superiority complex like her attitude on her next life, she's bound to double down when she finds out who dahlia really is i assume
wait kinda confused as to why florre is so obsessed to get revenge on dahlia? i mean...dont they have little interactions only? and what the heck did floree expect that a noble girl will openly welcome a commoner as their sister...i mean..yea im jos confuse y shes so set on with it..arent other people treating her bad too...?